The report gives results of an analytical study to assess the potential for sulfur retention in various types of coal-fired boilers. Results of a field test of 10 industrial coal-fired boilers were used to evaluate the impact on sulfur retention of the operating variables (load and excess O2). The effect of ash composition on sulfur retention was also evaluated, using a linear regression analysis. The expression % S Emitted = a+b (% Na2O/% CaO) + c (Load/100,000), where a, b, and c are constants, gave the best overall fit to the two pulverized coal-fired boiler data. The field test and regression analysis results were supported by equilibrium coal ash composition calculations over a range of temperatures and theoretical air for four coal ash compositions. The calculations show that significant fractions of the sulfur can be tied up as Ca and Na salts under both reducing and oxidizing conditions at temperatures below 250F. A minimum in the total condensed phase sulfur species is predicted at stoichiometric conditions for all temperatures.

"Industrial Environmental Research Laboratory, Office of Energy, Minerals, and Industry, Research Triangle Park, N.C." Nov. 1978. "Contract no. 68-02-1863, program element no. EHE624A." Includes bibliographical references.